Probing Conditions for Strong Clumping by the Streaming Instability: Small Dust Grains and Low Dust-to-gas Density Ratio

The streaming instability (SI) is a leading mechanism for concentrating solid particles into regions dense enough to form planetesimals. Its efficiency in clumping particles depends primarily on the dimensionless stopping time (\tau_s, a proxy for particle size) and dust-to-gas surface density ratio (Z). Previous simulations identified a critical Z (Z_{\rm{crit}})... Show more